Materials Data on Ca(BH)2 by Materials Project

Abstract

CaB2H2 crystallizes in the orthorhombic Pnma space group. The structure is two-dimensional and consists of two CaB2H2 sheets oriented in the (0, 0, 1) direction. Ca2+ is bonded in a distorted single-bond geometry to five H1- atoms. There are a spread of Ca–H bond distances ranging from 2.23–2.72 Å. There are two inequivalent B sites. In the first B site, B is bonded in a distorted single-bond geometry to three H1- atoms. There is one shorter (1.40 Å) and two longer (1.79 Å) B–H bond length. In the second B site, B is bonded in a distorted single-bond geometry to one H1- atom. The B–H bond length is 1.25 Å. There are two inequivalent H1- sites. In the first H1- site, H1- is bonded in a 3-coordinate geometry to one Ca2+ and two B atoms. In the second H1- site, H1- is bonded to four equivalent Ca2+ and two equivalent B atoms to form a mixture of distorted edge, corner, and face-sharing HCa4B2 octahedra. The corner-sharing octahedral tilt angles are 77°.